When the Detroit starter finally wobbled, Pittsburgh wasted little time knocking him over.

Pedro Alvarez's two-run double sparked a seventh-inning rally and the Pirates streaked by the Tigers 5-3 on Wednesday night. Travis Snider added an RBI double and Jordy Mercer laid down a perfect suicide squeeze to cap the four-run burst and abruptly end Sanchez's evening.

"I don't think as a team we ever check out in the seventh inning," Snider said. "We've had a lot of late comebacks we've had a lot of great rallies off bullpens and starters late in the game."

The victory was Pittsburgh's eighth of the year when it trailed after six innings and pushed the Pirates to a season-high 13 games over .500 (33-20). Bryan Morris (2-2) picked up the win in relief of A.J. Burnett.

Jason Grilli pitched the ninth for his major league-leading 22nd save.

Miguel Cabrera hit his 15th home run for Detroit. He flied out to the wall in right field with a runner on to end it.

Neil Walker - whose solo home run in the 11th inning produced the only run in a 1-0 Pittsburgh victory in Detroit on Tuesday night - provided the only two hits through off six innings off Sanchez. The righthander looked nearly as dominant as he did in his previous start, when he one-hit the Minnesota Twins.

Sanchez retired 16 of 17 batters at one point and appeared to have all the cushion he needed when Andy Dirks doubled home Don Kelly with one out in the fifth and Cabrera followed two batters later by poking a 92 mph fastball from A.J. Burnett into the seats in right field for his 15th home run, giving the Tigers a 3-1 lead.

Watching Sanchez buzz through the first six innings on just 67 pitches, Detroit manager Jim Leyland didn't even have anyone up in the bullpen when things quickly unraveled.Garrett Jones singled with one out in the seventh, Russell Martin walked on four pitches and the floodgates opened.

"It was kind of a freaky thing," Leyland said. "He just walked a guy and all of a sudden kind of lost it there momentarily."

Alvarez followed by driving a ball to the wall in left-center, scoring both runners. Snider took the next pitch and hit it off the wall in right with Alvarez just beating the relay throw to put Pittsburgh in front.

"We knew as hitters we had to grind," Snider said. "If he's going to make a mistake, it's going to be early. Pedro did a great job jumping on him early, so did Jones. Russell the same thing, getting on base. Before they were able to get anything going in their bullpen we were able to get to him in that inning."

Snider moved to third on a wild pitch, then darted home when Mercer's bunt stopped just in front of the pitcher's mound. It's one of the few times the squeeze has worked for the Pirates under manager Clint Hurdle.

"It was kind of surprising," Mercer said. "In those situations all you want to do is put it in fair territory somewhere. I was able to deaden it. It actually worked out really well for both sides."

Sanchez allowed five runs on seven hits in 6 2-3 innings, walking one and striking out nine while his ERA rose from 2.38 to 2.79.

"I think I missed some pitches and they hit them," Sanchez said. "I take responsibility, that's part of the game. Before that inning I thought everything was working good, especially location."Pittsburgh's late surge allowed Burnett to escape his fourth straight loss. The Pirates have struggled to support their ace this season and had scored just five runs total in his previous five starts.

The right-hander had issues with his command but managed to stay out of trouble until the fifth, when Kelly's leadoff walk started a three-run burst. Burnett gave up three runs on five hits, walking four and striking out four.

Burnett was long gone by the time Alvarez got things going. Tony Watson worked the eighth and Grilli - who struck out the Tigers in order in the 11th on Tuesday - stayed perfect in 22 save chances when Cabrera flied out.

NOTES: Detroit OF Torii Hunter sustained a contusion on his left elbow after getting hit by Morris' fastball in the seventh. Hunter said the pain made him "dizzy" but X-rays were negative. ... Tigers CF Austin Jackson is likely heading to Triple-A Toledo this weekend while he recovers from an injured left hamstring that's had him on the disabled list since May 12. Leyland said he'd like to test Jackson's hamstring before activating him ... A Pirates season ticket holder provided Grilli with a fish tank that includes three small sharks and a blowfish. Grilli and setup man Mark Melancon have nicknamed Pittsburgh's bullpen the "Shark Tank." ... The Pirates are 24-1 this season when leading after seven innings ... The series concludes on Thursday. Pittsburgh's Jeff Locke (5-1, 2.45 ERA) will look for his sixth straight victory. Doug Fister (5-2, 3.65 ERA) starts for the Tigers.